Ratchet action for car brake-operating mechanism



Nov. 17, 1931. w. D. BREWSTER I 1,832,805

RATCHET ACTION FOR CAR BRAKE OPERATING MECHANISM Filed March 5, 1928 2Sheets-She et 1 Lgyllll WITNESS Q BY 6 TT7 NEYS NOV. 17, 1931 D BREWSTER1,832,805

RATCHET ACTION FOR CAR BRAKE OPERATING MECHANISM Filed March 5, 1928 2Sheets-Sheet 2 W/ TNESS JW WW )4 7T0 ANEYS Patented 'Nov.. 17, 193iUNITED ESTATES PATENT OFFICE WILLIAM B. BREWSTER, or sYRAobsE, NEW Yo m,ASSIGNOR 'ro NATIONAL BRAKE "COMPANY INCORPORATED, OF BUFFALO, NEW YORK,.A-CORPORATION OF NEW YORK RATCHET Ac'rIoN r cAn'BnAKnornRaT-Iive;mncrrnmsm l Application filed March 5; 1928. Serial No. 259,162.

This invention relates to a ratchet action for car brake operatinmechanism of the class set forthxin my atent No. 1,487,531,

March 18,1924; i i 5 The drum with which the brake operating cable isengaged is operatively connected to aprimary driving shaft through themedium of speed-reducing and power-increasing train of gears, allrotating about parallel axes and preferably inplanes one above theother, the primary shaft being adaptedxto be operated by a hand wheelthrough the medium of a ratchet and pawl action capable of rotating thetrain of gears when the hand wheel is' turned in one direction fortensioning the cable to apply the brakes but permitting free rotarymovementof the hand wheel in theopposite direction independently of theratchet wheel. 7 i

Thetmain object is to enable the operator to apply the brakes with aminimumangular movement and also with a minimum loss of.

motion of the operating wheel and further more' toprevent excessivespinning of the hand wheel when its movement is reversed.

the brake-operating mechformly spaced relation circumferentially tooverlap progressively increasing distances upon adjacent ratchet teethso that successive pawls may be brought into engage'ment'with theratchet teethone at a time, with onlyslight angular movement of thehandwheel in a reverse direction from its brake-applying motion. i j Afurther object is to hold the pawls in operative engagement withtheteeth of the ratchet'wheel by means of springs of sufficient tensionto cause the pawls to drag upon said teeth and thereby to retard orprevent the backward spinning motion of the handwheel and pawls when thebrakes are released.

Qther objects and uses rel atinq to specific parts of the device will bebrought out in the following description.

In the drawings: Figure 1 a face view, partly broken away and partly insection, of a brake-operating mechanism embodying the various featuresof my mvention, the holding pawl for the gear train lbeing shown'by fulllines in its, Off position andby dotted lines in its On position. v 1 II Figure 2 is a vertical sectional view taken in'the plane of line 2'2,Figure 1. i

Figure 3 is a horizontal sectional View taken in the plane of line 33,Figure 1.

Figure at is .a vertical sectional 'viewv, taken in the plane of line4-41, Figure 2. r

- Figure 5'isadetail-vertical sectional view taken in the plane of line55 Figure 2, showing'more particularly the. bearing for the holding pawlor detent for the gear train.

Figure 6 is an enlarged face view of the centralport ion or hub of thehand wheel with the outer end plate removed to show the relat'iveposition of theseveral pawls and their actuating springs.

As illustrated, this-device comprises an up- I right cast metal frame orstandard -'1 engaged in a pressed steel casing -2' except that its baseis provided with laterally projecting flanges or feet adapted to restupon the floor of the car or other available support.

The majorport-ion of the cast metal frame -1 beween the base and topthereof is cored out to form an interior chamber -4' extending throughopposite sides thereof butnormal'ly closed'b-y. the adjacent sides ofthe steel casing 2% for receiving and inclos ing a; cable supportingdrum'-5- and a su'itable train of' speed reducing and power multiplyinggears -6-- connecting the cable supporting drum ,5- with a primaryoperating shaft *7' as shown more clearly in Fig- I "ure's 2 and 4.

. A chain or cable 8- is mounted upon the-drum -5 to be operated therebyand has one end connected to a suitable anchorage 9' on the4frame'1- andits other end adapted to be connected to, a brake mechaapplying andreleasing nism, not shown, for the brake;

The drum -5- and its coaxial gear the cross shaft --,11-,. said crossshafts and anchor pin -9 being mounted in suitable openings or hearingsin the frame 1- to extend through registering openin s in the i 1 steelcasing or housing 2 as hown in Figure 2 to permit them to be removedwhen necessary for repairs or replacements of the gears or drum withoutremoving the casing fom the frame or disturbing other-parts of theapparatus. For this latter purpose the opposite-sides of the upperportion of the case or housing 2 are provided with movable sections y12hinged at their lower ends at 13 lar form'of the sleeve -18: to

to the underlying portions of the casing and have their upper endsprovided w1th lugs 14.- and 15-- for-receiving a clamplng bolt 16whichis hinged at 17- to one of the lugs l4 and has its other end movableintoand out of aslot in the'other lug topermit quick clamping andreleasing of the sections -12- in and from their closed positions and,when opened, to permit access to the drum 5 and to the gears of thetrain 6-, it being understood that the sections -12, when closed, arebrought close together over the top of the frame 1,

as shown more clearly in Figures 1 and 4:. v v A tubular cross sleeve 18is journaled in suitable bearings in the front and rear sides of. theframe 1 above vthe gear-operating shaft -7 and is provided with anangular'intermediate portion for receiving the hub of a holdin pawl ordetent -v-19, Figure ,4, said hub angular opening corresponding to theangupermit the pawl toturn with the sleeve, I

This pawl 19 extends circumferential- 1y across, the perimeter of the,uppermost pinion of the gear train at one side thereof and is movableinto and out of vengagement with theteeth of the next adjacent gear forholding the gear train against return vmovement after being operated toset the brakes or, when shifted to its release position, permits thereverse operation of the gear train for releasing the brake. a

The means for operating the pawl --19 comprises, in this instance, awelghtedhand lever 2 0 secured to one end of a cross shaft rt-'-2lwhichis journaled in the tubular sleeve -18-*coaxial therewith and isprovided near its outer )end with a key or fin -22 vwhich ismovable in asegmental cir-' cular groove -Q3 in the outer enlarged end of the sleeve18 as shown in Figures 2 and 5.

arm on the outer endofthe shaft -421 The hand lever 20 constitutes acrank.

where it is accessible for operation at any time and has its outer endweighted to hold ing' a ratchet wheel -24 and eing Provided with) ".-25carrying a multiplicity of, in this in'-.

it in its different positions of adjustment as 1y hold the pawl 19-out-of engagement with its companion gear and when thrown to the otherside of the vertical position the fin --22,v will be brought intoengagement with the corresponding end of the slot or V groove 23-. torock the sleeve -18 and pawl 19 carried thereby into position todisengage the pawl from the gear train for releasing the brake. -20

That is, when the lever vertical position as shown by dotted lines in Fiure lthe fin 22- engages the other endwall of the slot -23- to rock theshaft in the opposite direction for engaging the pawl -l9 with theadjacent gear for holding the" brake in its applied position.

4 n aled in suitable bearings in the frame 1- parallel with'the. axes ofthe several gears 6- and rock shaft 21- to project. forwardlyfsomedistance beyond the adjacent side of the frame for IGCGlVlIl andsupporta hand wheel shaft .7 which is provided with a'threaded outer endengaged by a nut 27 fortightly clamping the ratchet wheel upon the shaftso that both mayrotate in unison.

The hand wheel 25-- is journaled upon I the inwardly extending end ofthevhub of the ratchet wheel '24- and has the central portion of itsouter end chambered to receive said ratchet wheel and pawls -26--.

The ratchet wheel is provided with a greater number-of uniform teeththan the number. of pawls -26-,' but not a multiple of the number ofpawls so that the latter may be made of uniform construction and stillbe able to overlap progressively increasing distancesupon adjacent teethwithout engaging more than one tooth at a time.

is rocked to the opposite side of the side of a vertical position itwill automaticalcorrespondingly tapered outer end of the When one pawlis engaged with any one of v p the teeth the remaining pawls willbearrange'd gradually increasing distances apart circumferentially sothat their free ends will overlap progressively increasing distancesupon adjacent'teeth.

" For-example, if, there are five pawls and i one of them is engagedwithone of the teeth the next succeeding pawl will be arranged tooverlap upon its adjacent toothone-fiftlr of motion.

the-tooth space, the next succeeding pawl twofifths, the thirdsucceeding pawl threefifths and-the fourth succeedingpawls four-fifths Iof such tooth spacethereby providing for the transmission of motion fromthe hand wheel to the ratchet wheel with a minimum lost When' rotatingthe hand wheel in the di rection indicated by arrow -ac' for 'transsmitting rotary motion to the ratchet wheel and thence through the mediumof the gear train for operating the drum and cable -53 to apply thebrakes this movement maybe limited to a relatively short are and thenreversed, in this instance only one-fifth of the tooth space, to obtaina fresh grip of another pawl with the ratchet wheel for continuing therotary movement in the direction indicated by the arrowthus providing aclose control of the brake in applying the same, it being understoodthat when the brake is set i the pawl-operating niember --v will beshifted to the position shown by dotted lines in Figure l for forcingthepawl into engagement with the larger gear -6 on the shaft 11 to holdthebrake in its set position.

X It will be observed, however, that immediately uponthe releasing ofthe pawl 19 from its holding position by shifting'its op-' eratin gmember 20 to the position shown by full lines in Figure l the directionof rotation of the ratchet wheel and handwheel will be-reversed. 1

The hub of the hand wheel -25'- is chambered at +28 from its outer endinwardly to receive. the ratchet wheel 24r and pawls .26'- which areprovided with cylindrical outer ends seated in corresponding cylindricalsockets .-29%- in the outer wall of said chamber as shown more'clearl inF'i ure 6 o a .y a

the circumferential lengths of the sockets and will beheld a adjacentends of the pawls being somewhat greater than a half circle so that whenthe pawls are placed-in operative position they gain st radial orcircumferential displacement- The outer open end of'the chamber isclosed-by agremovable cap or plate -'30-' which is heldin place byclamping screws or bolts 31 and serves to hold the pawls 26 againstoutward displacement, said bolts being engaged in apertured lugs 32projecting inwardly from the outer walls of the charber 28-1- betweenthe pawls-.-26-', Figure 6.

The free end's of the pawls ar-asp ring pressed intoengagement with theteeth of the ratchet wheel 2 l by flat leaf springs 33- having onev endengaged with the adme'nft of one of the jacent bosses and their otherends bearing against the outer, faces of the pawls while theirintermediate portions are adapted -to engage adjacent fulcrums -34 onthe outer wall of the chamber. v Operation When applying the brake thepawl-o'perating member 20 will be shifted to the position shown bydotted lines in Figure 1 to bring the free end of the pawl --1-9 intoengagement with the companion gear of the train-after. which the handwheel -251- will be rotated clockwise in the direction indicated byarrow wthus causing the engaging pawl 26' to effect a correspondingturning movement of the ratchet wheel '24- thereby actuating the geartrain and drum to apply the brake. I

It is preferable, however, to turn the hand wheel a part of a revolutionand then to reverse its motion'to engage one of the other one-fifth of atooth space in order to obtain successive gripping engagement of thepawls -'26 with the ratchet wheel 2 l.

t On the other hand, whenit is desired to re lease the brake pawl '19-may be'tripped from itsholding position throughthe nrnedi roe um of thehand lever '-2(l whereupon the motion of the gear train and drum will bereversed thus causing .a similar reversal of movement of the ratchetwheel '2 l-- and hand wheel-25 by reason of the engagepawls with theteeth of the ratchet wheel. The momentum of this reverse movement of thehand wheel tends to cause the latter to spin counter-clockwisearound theratchet clockwise spinning movement of the handwheel which, of course,is desirable in brake operating mechanisms of this character.

It will be observed that practically all of the'moving parts, except thehand wheel and adjacent portion of the shaft 7, are inclosed in aprotective housing, but access may be had to the interior mechanismatany time for repairsor adjustments by simply openllllD tie ' wheel butowing to the pressure of the pawls against the-teeth of the ratchetwheel by the springs -33- this pressure .acts as a drag upon the ratchetwheel to retard the counterint ing one or the otherofthe movablesections 12-- of the casing. I

The upper gear of the train on theshaft -7. is providedwith an angularopening therethrdugh for receiving the adjacent corresponding angularportion of the shaft, asshownin Figures 2 and 4, thereby assuring apositive drive of the gear train from the shaft when rotated by the handwheel-25--. What I claim is A car brake a ratchet .wheel secured toaxially from one end, a hand-Wheel journal'ed at one end on said hub andits other end I chambered to receive the ratchet wheel and provided withcylindrical sockets in the, periph'eralwalls of the chamber, pawlswithin said chamber having cylindrical outer ends journa-led in saidsockets, and leaf springs for yieldingly holding the inner ends of. thepawls against the ratchet teeth, each spring having its opposite endsengaged respectivev 1y. with the corresponding pawl and with the.

peripheral wall ofthe chamber in' the hand wheel, said wheel havininwardly projecting fulcruins engaging the Intermediate portions of thesprings and normally bowing the same inwardly to place the springsundertension. 7 In witness whereof I have hereunto set my 20th day ofFebruary 1928.-

hand this 7 WILLIATM D. BREWSTER.

h ogerating mechanism includmg arotary sha I the shaft and provided witha hub extending

